1. Field of the Invention
The invention relates to a cassette apparatus for recording and/or reproducing signals on a magnetic tape in a cassette (hereinafter referred to as a tape cassette recorder), which cassette may have one or more anti-erase openings for preventing the inadvertent erasure of a pre-recorded magnetic tape and more particularly to a tape cassette recorder having a housing; a head support which supports magnetic heads and is movable between an operating position near a cassette and a neutral position which is more remote from the cassette; a recording button which is manually movable from a inactive position to a recording position with a finger; a recording switching member connected to the recording button and operating a recording switch which electrically selects the recording or reproducing mode of operation; a sensor which detects the presence of an anti-erase opening by engaging the cassette rear wall at the known location for such openings, and at least partly projecting into the opening to assume a first position, while being in a second position in the absence of an opening; and blocking means for blocking the recording switching member in its inactive position when the sensor is in its first position.
Cassette equipment, which is manufactured in large quantities and available on the market in a wide variety, has greatly contributed to the advancement of magnetic tape as an audio-signal carrier. There is a trend towards ever-increasing perfection of cassette equipment and also towards making it cheaper so that it comes within reach of a larger public. Much attention is also paid to ease of operation. Modern inexpensive and portable cassette equipment, frequently combined with a radio, is operated by means of a number of push-buttons which are arranged side by side for controlling tape driving functions and audio playback.
Equipment of these types often has the capability to record audio signals on the magnetic tape they are generally referred to as cassette recorders. The commercially available cassette recorders usually have a recording button which can be depressed only if the cassette has a closed rear wall. When the cassette is provided with pre-recorded audio tracks by the manufacturer, so-called anti-erase openings are formed in the rear wall of the cassette. Location of such openings is standardized by International Electrotechnical Commission Publication 94A. These openings cooperate with components which may be provided in a cassette recorder to prevent the audio track from being inadvertently erased by the actuation of the recording button by a user.
2. Description of the Prior Art
Anti-erase interlocking is usually provided by blocking the movements of the recording button when a pre-recorded cassette is placed in the cassette apparatus. Generally, a pivotable sensor is mounted on the cassette apparatus near the rear of the cassette. The sensor allows movements of the recording button between its inactive and its recording position only when pressure against the closed rear cassette wall tilts the sensor.
To record audio signals on a non-prerecorded cassette, the button which starts the tape transport of the cassette recorder should be depressed in addition to the recording button. Upon depression the various buttons each engage with a locking slide, so that when a specific button has been depressed and subsequently another button is depressed the previously depressed button returns to its inactive position. Only the recording button and the starting button can be locked in their active positions at the same time; however, the two keys must then be depressed simultaneously.
Simultaneous key depression is a particular problem with cheap portable cassette recorders, which are light and small. Actuating the recording button and the starting button, by pressing with two fingers of one hand while the other hand supports the cassette recorder to take up the reaction force, is not always convenient.